With advances in densification of semiconductor devices, the demand is rapidly increasing for IC packages such as a ball grid array (BGA) or pin grid array (PGA), in which connecting solder balls are arranged in an array form or in a matrix form as electrodes, or a land grid array (LGA), in which solder balls are not mounted.
For these IC packages, the pitch between the electrodes tends to decrease from 1.0 mm to 0.8 mm to 0.5 mm with the densification of semiconductor devices.
Generally, the semiconductor devices are subject to a burn-in test after being manufactured. In the burn-in test, a semiconductor device is mounted on an IC socket and heated under predetermined conditions to check the electrical properties thereof.
Conventionally, for the IC socket, contact pins in contact with the electrodes of semiconductor device are embedded in a synthetic resin so that the pitch thereof is equal to that of the electrodes of semiconductor device. One end of the contact pin comes into contact with the electrode of semiconductor device, and a leg extending to the outside of socket at the other end is inserted into and connected to a printed board, and further connected to an external tester or the like.
This printed board not only is a wiring board but also has a function of enlarging and changing the minute pitch of contact pins, which has been set so as to be equal to the pitch between electrodes of semiconductor device, to a pitch between connecting terminals for the external tester or the like. For example, the pitch of contact pins of 1.0 mm is enlarged and changed to 1.27 mm or 2.54 mm, the pitch between connecting terminals for the external tester, or when the electrode arrangement of semiconductor device is of a matrix form, the arrangement of contact pins is enlarged and changed in the matrix form, or the arrangement itself is changed.
As the pitch between electrodes of semiconductor device decreases and a two-dimensional electrode arrangement such as a matrix-form arrangement is used, a multilayer printed board of 4 to 8 layers or 10 layers etc. must be used as a printed board for enlarging and changing the pitch of contact pins in the IC socket.
However, if the printed board is made multilayered, there arises a problem in that the manufacturing cost increases, and therefore the cost required for the burn-in test of the semiconductor device also increases.
The present invention was made in view of the above situation, and accordingly an object thereof is to provide an IC socket capable of inspecting the electrical properties of a semiconductor device at a low cost without using an expensive multilayered printed board.